Hi Christine. The water is in the low to mid 50s right now which is very cold to someone who isn’t properly acclimated to cold water swimming. So a wetsuit is a good idea. I don’t personally wear them so I’m no expert on the best place to go, but I’d check out Paragon Sports on Broadway and 18th. There’s also a dive shop near there called Leisure Pro but I’m not sure how much swimming gear they’d have vs diving gear. You can also ask Jackrabbit Sports if they still carry Tri gear – they seemed to change their focus to only running in the past couple of years. I think REI in SoHo probably carries wetsuits as well.